Rubber composition and method of preserving rubber



Patented Mar. 24, 1931 UNITED STATES PATENT OFFICE- MARION G. REED, OF AKRON, OHIO, ASSIGNOR TO THE B. F. GOODRIOH COMPANY, OF

NEW YORK, N. Y., A CORPORATION OF NEW YORK RUBBER COMPOSITION AND METHOD OF PRESERVING RUBBER No Drawing. Application filed November 6, 1928. Serial No. 320,004.

This invention relates to the art of preserv parts, palm oil 5 parts, and hexamethylene ing rubber, either in the vulcanized or untetramine 0.75 parts. One portion was used vulcanized condition, and to rubber composias a control, while other portions were furtions so preserved. ther mixed with 0.95 parts (0.5% of the com- It is well known that many materials posposition) of the Various addition products sess the property of retarding the deterioraprepared as indicated above. The composition which rubber normally undergoes when tions were thoroughly mixed, and vulcanized exposed to light, heat, and air. These matein a press for 45 minutes at 294 F. to produce rials known to those skilled in the art as an optimum cure. The relative rates of aging anti-oxidants or age-resisters, are cusof the various vulcanized compositions were tomarily incorporated into the rubber compocompared by meausuring their respective tensition before it is vulcanized. Among such sile strengths and elongations before and age-resistors which have heretofore been after aging. Accelerated aging tests were proposed, organic nitrogen compounds such carried out in the Geer aging oven, in which 5 as the amines and especially the secondary samples were maintained at a temperature aromatic amines have been particularly sucof 158 F. ina constantly renewed stream of cessful. The object of this invention is to air, as well as in the Bierer-Davis bomb, in provide a new and inexpensive class of el which other samples were maintained at the cient age-resisters, and age-resisting rubber same temperature (158 F.) in an atmosphere 0 compositions comprising such age-resistors. of oxygen at a pressure of 300 lbs. per sq. in.

This invention, in brief, consists in treating In the table below T indicates ultimate tenrubber with the addition product or a secsile strength in lbs. per sq. in. and E indicates ondary aromatic amine with an aromatic nitro ultimate elongation in per cent. of original compound. Such addition products may be length.

formed by melting the secondary amine to Aging tests of addition products gether with the nitro compound or even by dISSOlVlII the two materials separately in a b After7da fter 43 solvent in whlch the addition product is sub- Before aging in the Geer Q EE Q stantially insoluble and mixing the solutions, Ageqesister oven bomb 30 whereby the product is precipitated. Addr- 0 tion products may thus be prepared from d1- T E T E 'r E phenylamine, phenyl-alpha-naphthylam1ne, phenyl-beta-naphthylamine, alpha or beta None tr 3405 673 1842 480 781 291 dinaphthylamine, phenyl-toluidme, tolyl- Phepyl-beta-naphthyl- 35 pthyl d ph yl p ph y1 d amine+p nitrotoluenen 3343 662 2526 570 2334 580 0 P h o n yl beta-naphthylamine, etc. when combined with nlt f b a amine+dinitrobenzene 3280 675 2621 583 2390 580 nitrotoluene, nitronaphthalene, dlnitroben- Ph 1 b t h h I eny-ea-na t Z6116 zi l i abp d: amine+trinitrot )1uez i e 3468 697 2567 567 2400 553 chlor-nitrobenzene, chloimitro enzene, m- Phenyl bem naphthyl g0 traniline, nitro-naphthylamlne, etc. amiue+picric acid 3238 687 2779 590 2500 610 Ewample 1.For example, a series of products was prepared by mixing equimolecular Ex m l 2, F th dditi d t amounts of phenyl-beta-naphthylamine and were prepared from chlorinated nitro coma nitro compound. These were melted topounds and secondary amines, specifically (g gether until the mixture was homogeneous, from 2,4 dinitro-chlorbenzene with diphenyland were then allowed to cool. A typical tire amine d henyLalpha-naphthylarnine, and tread composition was then prepared cono-nitro-chlorbenzene with phenyl-beta-naphtaining blended plantation rubbers parts thylamine. These products were incorpoby weight, sulfur 5.5 parts, zinc oxide 30 rated into rubber compositions in the same parts, gas black 40 parts, mineral rubber 10 proportions as in Example 1 and were tested W3 in the same manner. The results are shown in the following table.

Aging tests of addition products After 48 store a ing i iii d i hours g event BierereDaws Aglsresisteu bomb T E T E T E None (control) 3959 638 ;218?;- 473 81m ;3PJ'

2,4 dinitro-chlorbenzene. w +diphenylumina- 418i i 685- 231-1' 567- 2396 563- i 2,4 dinitro-chlorbenzene v +phenyl -a1pha naphthylamiue 4074 665 3193 633 2589 530 O -uitto clilorlienzenyk E I phen'yhlieta uapfithylsmineninsi .i 4086 i 645.:2671 5154 0 557 From-the above results it is evident that theadditioni products ozt secondary aromatic amines with: aromatic. nitro com-pounds are ertremely eifective age-resisters The reason for the excellent anti-oxidant properties of these addition products is: not understood The aromatic nitro compoui-ids alone are not azgerresisters, sometimes even accelerating the deterioration of. rubber, and. their addition products: with. such non-nitrogenous come poimrlsasnaphthalene-have no beneficial effect upon theaging oli rubber. The addition. products ot the nitric-compounds with other amines, such as the primary aromatic amines, cycli-camines, etc, have also been found to possess age-resisting properties although they are not as active as those hereiarabove described. For example, theaddition products oat nitro-compou-ndswith aniline, alpha-naphthylamine, (Lu-inaldine, etc, have been found to have value as age-resistors. The exact character of the addition products of nitro compounds and amines hasnot been. determined. It is known that they are formed from various proportions of the materials, for example, either one or two molecular equivalents of the nitrocompounds to one of the amine, but the only theories relating tothe mechanism of. the adremained entirely unsubstantiated.

Ageesisters of this class may also be formed the rubber beforeor during vul-- canization by the separate incorporation of the nitro compounds and the amines. The

addition products may also be-applied to unvulcanized or vulcanized rubber with good effect on the age-resisting properties of the rubber such as by applying; them to the surface of the rubbezmas for example in solution,

or in the form. of a powder, paste, .or suspension;

It. is to be understood that the term treating. as employed in the appended claims is used in a generic sense to include either the incorporation of the addition products of d'i'tion which have so far been proposed have nitro compounds and amines into the rubber by milling or similar process or by addition to the rubber latex before coagulation, or to the application thereof to the surface of a mass of crude or Vulcanized rubber. The term rubber is likewiseemplo ed in the claims: in at generic sensel-flo inn e caoutchouc balata, gutt'a-pcrclia', rubber isomers,

' and like products, whether or not admixed withz fillersppiginents, vulcami'rzingr omacceh- I crating agentssfl I claim: 1 l he method of preserving rubber which comprises treating rubber with the addition product of'an aromaticmtro compound'witlr a secondary aromatic amine.

2;. The method of preserving rubber which. comprises treating rubber with the; addition. product of'a nitrated benzene derivative with. a secondary aromatic. amine.

The. method of. preserving, rubber. which comprises. treating rubber. with the addition product of anitrated benzene derivative with an. ar ,l-naphthylamind A. The method-of preserving. nubher which. comprises treating rubber with the addition product of dinitro chlorbenzene with. an arylnaphthylamine.

The method of preserving rubber which comprises treating rubber with the addition. product. of. dinitro-chlorbenzene. with phenylbeta-naphthylamine.

6. A composition of matter comprising, rubber and the addition product. of. an arc-- inatic nitro compound with. a secondary aron-iatic amine.

T. A composition of matter comprising rubber and the addition product of. nitrated benzene derivative with a secondary aromatic. amine.

8. A composition of matter comprising, rubber and the addition roduct of a nitrated benzene derivative wi' an arylsnaphthyL ill-111116..

9-. A composition of matter comprising rubber and the addition product oii din-itrochlo-rbenzene with an aryl-naphthylamine.

10. A compositionof matter comprising rubber and; the addition product of diuitrochlorbenzene with phenyl-betasnaphthylamine.

11;. A product resulting from the vulcanization of a composition comprising rubber a vulcani-zing agent, anaccelerator of vulcanization and the addition product oi an aromatic nitro compound with a secondary aromatic amine.

12.. A. product resulting from. the vulcanization of a com-position comprising rubber, a vulcanizing agent, anaccelerator of. Vulcanization and the addition product of (ii nitro-chlorbenzene with phenyl-beta-naphs thylami-ne,

13. The method of preserving rubber which comprises vulcanizing, rubber in the presence of the addition product of an aromatic nitro compound with a secondary aromatic amine.

14. The method of preserving rubber which comprises vulcanizing rubber in the presence of the addition product of a nitrated benzene derivative with an a-ryl-naphthylamine.

15. The method of preserving rubber which comprises vulcanizing rubber in the presence of the addition product of dinitrochlorben- Zene with phenyl-beta-naphthylamine.

In witness whereof I have hereunto set my hand this 12th day of November, 1928.

MARION C. REED. 

